An X-ray source

Abstract

The present invention discloses an X-ray source comprising an electron source for generating a long-pulsed, low-energy electron beam, a superconducting linear accelerator for accelerating the low-energy electron beam, and an X-ray target for generating X-rays through the action of the electron beam. The electron source is connected to the superconducting linear accelerator via a first beam transmission line, and the superconducting linear accelerator is connected to the X-ray target via a second beam transmission line. This invention addresses the problem that conventional X-ray sources based on room-temperature linear accelerators cannot produce long-pulsed X-rays.

Description

Technical Field

[0001] The present invention relates to the technical field of ray sources, and in particular to an X-ray source. Background Art

[0002] In 1895, German scientist Wilhelm K. ) accidentally discovered X-rays while conducting gas discharge experiments in cathode ray tubes, and for this discovery he was awarded the first Nobel Prize in Physics in 1901. Since then, X-rays have been widely used and developed as a powerful tool in medicine, industry, basic and applied scientific research, and other fields.

[0003] X-ray sources are divided into ordinary X-ray tubes and accelerator-based X-ray sources. There are two ways to generate X-ray sources based on accelerators, electron beam targeting and synchrotron radiation. The principle of generating X-rays by electron beam targeting is the same as that of ordinary X-ray tubes, both of which are bremsstrahlung generated by the interaction between the electron beam and matter. The accelerator system is used to generate the electron beam required for targeting. The pulse length of the X-rays generated by electron beam targeting is the same as the pulse length of the electron beam. Conventional room-temperature radio frequency accelerator systems cannot provide electron beams with long pulse widths (microseconds to milliseconds, or even hundreds of milliseconds or continuous time states). Similarly, the X-ray source based on this scheme cannot provide X-rays with the same long pulse width.

[0004] In view of the above problems, the present invention is proposed. Summary of the Invention

[0005] An object of the present invention is to provide an X-ray source, which overcomes the problem that existing X-ray sources cannot provide long-pulse X-rays.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An X-ray source includes an electron source for generating a long-pulse low-energy electron beam, a superconducting linear accelerator for accelerating the low-energy electron beam, and an X-ray target for generating X-rays through the action of the electron beam. The electron source is connected to the superconducting linear accelerator via a first beam transmission line, and the superconducting linear accelerator is connected to the X-ray target via a second beam transmission line.

[0008] Preferably, the duration of the long pulse low-energy electron beam generated by the electron source is adjustable within a range of 10 microseconds to 1 second.

[0009] Preferably, the electron source includes a driving laser, a photocathode and an anode, the driving laser emits laser light incident on the photocathode to generate electrons, and the extraction electric field between the photocathode and the anode draws the electron bunch out of the photocathode and incident on the first beam transmission line.

[0010] Preferably, the laser emitted by the driving laser is a laser with adjustable pulse length, so that the pulse time length of the electron beam generated by the electron source can be adjusted. The driving laser adjusts the length of the laser pulse by adjusting the length of the voltage signal.

[0011] Preferably, the electron source is a DC high-voltage electron source formed by a DC high-voltage electron gun or a radio-frequency electron source formed by a radio-frequency electron gun. The extraction electric field formed by the DC high-voltage electron source is a static high-voltage electric field, and the extraction electric field formed by the radio-frequency electron source is a radio-frequency electromagnetic field.

[0012] Preferably, the lateral emittance of the low-energy electron beam generated by the electron source is lower than 10 mm*mrad.

[0013] Preferably, the superconducting linear accelerator includes radio frequency resonant cavities distributed along an axis, and the radio frequency resonant cavities are driven by a radio frequency power source.

[0014] Preferably, the radio frequency resonant cavity is placed in a low temperature environment of 4K or 2K.

[0015] Preferably, the X-ray target comprises a high atomic number material. Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention provides an X-ray source, which can provide X-rays with long pulse width, and the X-ray source can control the pulse time length of the X-rays by adjusting the length of the electron beam pulse. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 Schematic diagram of the structure of the X-ray source.

[0019] In the figure: 1—electron source, 2—first beam transmission line, 3—superconducting linear accelerator, 4—second beam transmission line, 5—X-ray target. DETAILED DESCRIPTION

[0020] The core of the present invention is to provide an X-ray source, which overcomes the problem that existing X-ray sources cannot provide long-pulse X-rays.

[0021] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of this application.

[0022] like Figure 1 As shown, the X-ray source provided in this specific embodiment includes an electron source 1, a superconducting linear accelerator 3 and an X-ray target 5. The electron source 1 is connected to the superconducting linear accelerator 3 through a first beam transmission line 2, and the superconducting linear accelerator 3 is connected to the X-ray target 5 through a second beam transmission line 4. The electron source 1 and the superconducting linear accelerator 3 can operate together to generate a relativistic electron beam.

[0023] Electron source 1 generates a long-pulsed, low-energy electron beam BE1 with a first energy E1. The energy of low-energy electron beam BE1 is approximately 300 kV, and the pulse duration of the low-energy electron beam generated by electron source 1 is adjustable from 10 microseconds to 1 second. Electron source 1 comprises a driving laser, a photocathode, and an anode. The driving laser emits laser light incident on the photocathode, generating electrons. The extraction electric field between the cathode and anode draws the electron bunch out of the photocathode and into a first beam transmission line 2. The first beam transmission line 2 transmits the low-energy electron beam BE1 generated by electron source 1 to a superconducting linear accelerator 3.

[0024] The low-energy electron beam BE1 is generated by the driving laser through the action of the photocathode. The low-energy electron beam BE1 and the driving laser have the same time structure. The laser emitted by the driving laser is a laser with adjustable pulse length, so as to realize the adjustable pulse time length of the electron beam generated by the electron source 1. The driving laser adjusts the length of the laser pulse by adjusting the length of the voltage signal.

[0025] Electron source 1 is a DC high-voltage electron source formed by a DC high-voltage electron gun or an RF electron source formed by an RF electron gun. The extraction electric field formed by the DC high-voltage electron source is a static high-voltage electric field, while the extraction electric field formed by the RF electron source is a radio-frequency electromagnetic field. In this specific embodiment, electron source 1 employs a DC high-voltage electron gun that generates a low-energy electron beam BE1 having an energy of approximately 300 kV. The extraction electric field of the DC high-voltage electron gun is a static high-voltage electric field formed between the cathode and anode by a DC high-voltage power supply.

[0026] As a preference in this specific embodiment, the low-energy electron beam BE1 has a relatively low lateral emittance. Preferably, the lateral emittance is lower than 10 mm*mrad.

[0027] The surface resistance of the superconducting cavity of the superconducting linear accelerator 3 is about 6 orders of magnitude smaller than that of the room temperature cavity. Even considering the loss of the refrigerator, the total loss is hundreds of times smaller than that of the room temperature cavity. The superconducting linear accelerator 3 can operate in continuous wave or pulsed mode at higher acceleration gradients and beam currents, which allows longer pulses. The superconducting linear accelerator 3 can accelerate long pulse electron beams, which can meet the requirements of the present invention. The superconducting linear accelerator 3 includes a radio frequency resonant cavity distributed along the axis, which is driven by multiple radio frequency power sources. The radio frequency resonant cavity of the superconducting linear accelerator 3 is placed in a low temperature environment of a 4K or 2K low temperature tank to ensure the superconducting state of the radio frequency resonator. The low energy electron beam BE1 obtains an energy gain ΔE in the superconducting linear accelerator 3 to obtain a high energy electron beam BE2. The high energy electron beam BE2 and the low energy electron beam BE1 have the same time structure. The time length of the high energy electron beam BE2 is adjusted by adjusting the length of the low energy electron beam BE1. The time length of the low energy electron beam BE1 is adjusted by adjusting the length of the laser pulse emitted by the driving laser. ΔE is determined by the scale and performance of the superconducting linear accelerator 3. The greater the number of RF resonant cavities and the greater the field gradient, the greater the energy gain ΔE. Theoretically, ΔE can range from a few MeV to several GV, or even to infinity. In this embodiment, ΔE is approximately 8 MeV.

[0028] The high-energy electron beam BE2 strikes the X-ray target 5 along the second beam transmission line 4. The X-ray target 5 must have a cooling function to prevent the energy deposited by the high-energy electron beam BE2 from burning the X-ray target 5. The core component of the X-ray target 5 is selected from a high-atomic-number material. The high-energy electron beam BE2 and the high-atomic-number material interact to produce X-rays. In this specific embodiment, the high-atomic-number material is tungsten.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0030] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An X-ray source, characterized in that: The invention comprises an electron source for generating a long-pulse low-energy electron beam, a superconducting linear accelerator for accelerating the low-energy electron beam, and an X-ray target for generating X-rays by the action of the electron beam, wherein the electron source is connected to the superconducting linear accelerator via a first beam transmission line, and the superconducting linear accelerator is connected to the X-ray target via a second beam transmission line; The duration of the long pulse low energy electron beam generated by the electron source is adjustable, and the adjustment range is 10 microseconds to 1 second; The electron source includes a driving laser, a photocathode and an anode. The driving laser emits laser light that is incident on the photocathode to generate electrons. The extraction electric field between the photocathode and the anode draws electron bunches out of the photocathode and into the first beam transmission line. The laser emitted by the driving laser is a laser with adjustable pulse length, so that the pulse time length of the electron beam generated by the electron source can be adjusted. The driving laser adjusts the length of the laser pulse by adjusting the length of the voltage signal; The superconducting linear accelerator includes a radio frequency resonant cavity distributed along an axis, and the radio frequency resonant cavity is driven by a radio frequency power source; The radio frequency resonant cavity is placed in a low temperature environment of 4K or 2K.

2. The X-ray source according to claim 1, wherein The electron source is a DC high-voltage electron source formed by a DC high-voltage electron gun or a radio-frequency electron source formed by a radio-frequency electron gun. The extraction electric field formed by the DC high-voltage electron source is a static high-voltage electric field, and the extraction electric field formed by the radio-frequency electron source is a radio-frequency electromagnetic field.

3. The X-ray source according to claim 1, wherein The electron source generates a low-energy electron beam with a lateral emittance lower than 10 mm*mrad.

4. The X-ray source according to claim 1, wherein The X-ray target comprises a high atomic number material.

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